Spitzer Albedos of Near-Earth Objects

Annika Gustafsson, David E Trilling, Michael Mommert, Andrew McNeill, Joseph L. Hora, Howard A. Smith, Stephan Hellmich, Stefano Mottola, Alan W. Harris

Research output: Contribution to journalArticle

Abstract

Thermal infrared observations are the most effective way to measure asteroid diameter and albedo for a large number of near-Earth objects (NEOs). Major surveys like NEOWISE, NEOSurvey, ExploreNEOs, and NEOLegacy find a small fraction of high albedo objects that do not have clear analogs in the current meteorite population. About 8% of Spitzer-observed NEOs have nominal albedo solutions greater than 0.5. This may be a result of light-curve variability leading to an incorrect estimate of diameter or inaccurate absolute visual magnitudes. For a sample of 23 high-albedo NEOs we do not find that their shapes are significantly different from the McNeill et al. NEO shape distribution. We performed a Monte Carlo analysis on 1505 NEOs observed by Spitzer, sampling the visible and thermal fluxes of all targets to determine the likelihood of obtaining a high albedo erroneously. Implementing the McNeill shape distribution for NEOs, we provide an upper limit on the geometric albedo of 0.5 0.1 for the near-Earth population.

Original languageEnglish (US)
Article number67
JournalAstronomical Journal
Volume158
Issue number2
DOIs
StatePublished - Jan 1 2019

Keywords

  • asteroids: Near-Earth Objects
  • Astronomical Methods: Infrared Astronomy, Visible Astronomy
  • Astronomical Reference Material: Surveys
  • Astronomical Techniques: Photometry

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Gustafsson, A., Trilling, D. E., Mommert, M., McNeill, A., Hora, J. L., Smith, H. A., Hellmich, S., Mottola, S., & Harris, A. W. (2019). Spitzer Albedos of Near-Earth Objects. Astronomical Journal, 158(2), [67]. https://doi.org/10.3847/1538-3881/ab29ea